Depends on your carrier or if you've swapped roms... because If I remember the analogs are not working on Sprint devices.. OR it is that they don't work if you want background on all pages... can't recall exactly.
It's a lot of reading but its best to get as much info as you can before you jump!
Start here...
http://forum.xda-developers.com/showthread.php?t=420887
Collections here...
http://forum.xda-developers.com/show...37#post2784137